Also involved are the specifics of architecture, icons, liturgical music, vestments and traditions which have evolved over the centuries in the practice of this rite. Traditionally, the congregation stands throughout the whole service, and an iconostasis separates the sanctuary from the nave of the church. The faithful are very active in their worship, making frequent bows and prostrations, and feeling free to move about the temple (church building) during the services. Also, traditionally, the major clergy and monks neither shave nor cut the hair or beards.

Scripture plays a large role in Byzantine worship, with not only daily readings but also many quotes from the Bible throughout the services. The entire psalter is read each week, and twice weekly during great lent.

Fasting is stricter than in the West. On fast days, the faithful give up not only meat, but also dairy products, and on many fast days they also give up fish, wine and the use of oil in cooking. The rite observes four fasting seasons: Great Lent, Nativity Fast, Apostles' Fast and Dormition Fast. In addition, most Wednesdays and Fridays throughout the year are fast days and many monasteries also observe Monday as a fast day.

There are two ancient liturgical traditions from which all of the Eastern Rites (plus the Gallican Rite in the West) developed: the Alexandrian Rite in Egypt and the Antiochene Rite in Syria. These two Rites developed directly from practices of the Early Church. Of these two traditions, the Rite of Constantinople developed from the Antiochene Rite. Prior to the see of Constantinople's elevation to the dignity of patriarch by the Second Ecumenical Council in 381, the primary jurisdiction in Asia Minor was the Patriarchate of Antioch. With the council's elevation of Constantinople to primacy in the East, with the words "The Bishop of Constantinople ... shall have the prerogative of honour after the Bishop of Rome; because Constantinople is New Rome",[1] the Constantinopolitan Rite gradually came to be the standard usage in every place under its jurisdiction.

Because the Rite of Constantinople evolved as a synthesis of two distinct rites — cathedral rite of Constantinople called the "asthmatiki akolouthia" ("sung services") and the monastic typicon of the Holy Lavra of Saint Sabbas the Sanctified near Jerusalem — its offices are highly developed and quite complex.

Further developments continued to occur, centered mostly around Constantinople and Mount Athos. Monasticism played an important role in the development of the rituals. In Constantinople, the work of the monastery of the Studion greatly enriched the liturgical traditions, especially with regard to the Lenten observance. Iconography continued to develop and a canon of traditional patterns evolved which still influences Eastern religious art to this day.

Historical events have also influenced the development of the liturgy. The great Christological and Trinitarian controversies of Late Antiquity are reflected in the glorifications of the Trinity heard in the numerous ekphonies encountered during the services. In response to Nestorius' attack on giving the title of Theotokos to the Virgin Mary, the Byzantines increased the use of the term in the liturgy, and now almost every string of hymns ends with one in her honour, called a theotokion.

All liturgical rites change and develop over time. As new saints are canonized, new hymns are composed; as new needs arise, new prayers are written. The rite also profits from the fact that the Christian East is not so centralized in ecclesiastical polity as the West. This allows for greater diversity, and as members of one church visit another, a natural cross-pollination occurs with resultant enrichment on all sides. In spite of its great emphasis on tradition, the Byzantine Rite comprises a constantly growing and expanding ritual, with room for local practice.

The tradition of the Church of Constantinople ascribes the oldest of its two main Divine Liturgies to St. Basil the Great (d. 379), Metropolitan of Cæsarea in Cappadocia. This tradition is confirmed by the witness of several ancient authors, some of whom were contemporaries.[2][3][4] It is certain that St. Basil made a reformation of the Liturgy of his Church, and that the Byzantine service called after him represents his reformed Liturgy in its chief parts, although it has undergone further modification since his time.[5] St. Basil himself speaks on several occasions of the changes he made in the services of Cæsarea.[6][7] and other contemporary witnesses attest his arrangement of the services. Basil had as his goal the streamlining of the services to make them more cohesive and attractive to the faithful. He also worked to reform the clergy and improve the moral life of Christians. He shortened the services and wrote a number of new prayers. The most important work attributed to him is the Divine Liturgy of St. Basil. He took as his basis the Liturgy of St. James as it was celebrated at his time in the region of Cappadocia, as well as some liturgical elements recorded in the Apostolic Constitutions.[5] Over time, the Liturgy of Saint Basil gained wide usage in Asia Minor and Syria. Peter the Deacon mentions that Basil's Liturgy was "used by nearly the whole East";[5] however, the Coptic rite uses another Liturgy which is also attributed to Saint Basil,[8] so Peter the Deacon's reference may not be to the Liturgy of St. Basil used in the Byzantine Rite.

The divine liturgy is normally not celebrated daily except in cathedrals and larger monasteries. However, most parishes and smaller monasteries serve the Liturgy on Saturdays, Sundays, and major feast days throughout the year.

When a bishop officiates, the divine liturgy has an expanded form with particular solemnity; though other services are also affected by being officiated by a bishop, none is more so than the liturgy.

The typica is used whenever the divine liturgy is not celebrated at its usual time, i.e., when there is a vesperal liturgy or no liturgy at all. On days when the liturgy may be celebrated at its usual hour, the typica follows the sixth hour (or matins, where the custom is to serve the Liturgy then) and the Epistle and Gospel readings for the day are read therein;[note 5] otherwise, on aliturgical days or when the Liturgy is served at vespers, the Typica has a much shorter form and is served between the ninth hour and vespers.[note 6]

Also, there are Inter-Hours for the First, Third, Sixth and Ninth Hours. These are services of a similar structure to, but briefer than, the hours. their usage varies with local custom, but generally they are used only during the Nativity Fast, Apostles Fast, and Dormition Fast on days when the lenten alleluia replaces "God is the Lord" at matins, which may be done at the discretion of the ecclesiarch when the Divine Liturgy is not celebrated.

In addition to these public prayers, there are also private prayers prescribed for both monastics and laypersons; in some monasteries, however, these are read in church. These include Morning and Evening Prayers and prayers (and, in Russia, canons) to be prayed in preparation for receiving the Eucharist.

The sundry Canonical Hours are, in practice, grouped together into aggregates[note 7] so that there are three major times of prayer a day: Evening, Morning and Midday.[note 8] The most common groupings are as follows:

On the eves before Great Feasts and, in some traditions, on all Sundays, this grouping is used. However, the All-night vigil is usually abridged so as to not last literally "all-night" and may be as short as two hours; on the other hand, on Athos and in the very traditional monastic institutions, that service followed by the hours and Liturgy may last as long as 18 hours.

Afternoon — Ninth Hour, Little Vespers,[note 12] Compline (where it is not read at the commencement of the Vigil)

Early night — Compline (where it is not the custom for it to follow small vespers), Great Vespers,[note 13] a reading, Matins, First Hour

When the feast is a weekday (or, in the Russian tradition, on any day for Christmas, Theophany), Vespers (with the Liturgy in most instances) is served earlier in the day and so Great Compline functions much as Great vespers does on the vigils of other feast days.

Evening — Great Compline (in some traditions) and, if there be an All-Night Vigil, the reading, matins, first hour.

Two main strata exist in the rite, those places that have inherited the traditions of the Russian Church which had been given only the monastic Sabbaite typicon which she uses to this day[note 14] in parishes and cathedrals as well as in monasteries, and everywhere else where some remnant of the cathedral rite remained in use; therefore, the rite as practiced in monasteries everywhere resembles the Russian recension, while non-Russian non-monastic customs differs significantly. For example, in the Russian tradition, the "all-night vigil" is served in every church on Saturday nights and the eves of feast days (all though it may be abridged to be as short as two hours) while elsewhere, it is usual to have matins on the morning of the feast; however, in the latter instance, vespers and matins are rather less abridged but the Divine Liturgy commences at the end of matins and the hours are not read, as was the case in the extinct cathedral rite of Constantinople.

Also, as the rite evolved in sundry places, different customs arose; an essay on some of these has been written by Archbishop Basil Krivoshein and is posted on the web.[9]

Into this fixed framework, numerous moveable parts of the service are inserted. These are taken from a variety of liturgical books:

Psalter (Greek: Ψαλτήρ(ιον), Psalter(ion); Slavonic: Ѱалтырь or Ѱалтирь, Psaltyr' ) A book containing the 150 Psalms[note 15] divided into 20 sections called Kathismata together with the 9 Biblical canticles which are chanted at Matins; although these canticles had been chanted in their entirety, having over time come to be supplemented by interspersed hymns (analogously to stichera) to form the Canon, the canticles themselves are now only regularly used in a few large monasteries[note 16] The Psalter also contains the various "selected psalms", each composed of verses from a variety of psalms, sung at matins on feast days, as well as tables for determining which Kathismata are to be read at each service; in addition to the Psalms read at the daily offices, all the Psalms are read each week and, during Great Lent, twice a week.

Octoechos (Greek: Ὀκτώηχος; Slavonic: Октоихъ, Oktoikh or Осмогласникъ, Osmoglasnik)—Literally, the Book of the "Eight Tones" or modes. This book contains a cycle of eight weeks, one for each of the eight echoi (church modes of the Byzantine musical system of eight modes), providing texts for each day of the week for Vespers, Matins, Compline, and (on Sundays) the Midnight Office. The origins of this book go back to compositions by St. John Damascene.

Menaion (Greek: Μηναίον; Slavonic: Минеѧ, Mineya)—A twelve-volume set which provides liturgical texts for each day of the calendar year,[note 17] printed as 12 volumes, one for each months of the year.[note 18] Another volume, the General Menaion contains propers for each class of saints for use when the propers for a particular saint are not available. Additionally, locally venerated saints may have services in supplemental volumes, pamphlets, or manuscripts.

Menologion A collection of the lives of the saints and commentaries on the meaning of feasts for each day of the calendar year, also printed as 12 volumes,[note 18] appointed to be read at the meal in monasteries and, when there is an all-night vigil for a feast day, between vespers and matins.

Pentecostarion (Greek: Πεντηκοστάριον, Pentekostarion; Slavonic: Цвѣтнаѧ Трїωдь, Tsvetnaya Triod' , literally "Flowery Triodon"; Romanian: Penticostar) This volume contains the propers for the period from Pascha to the Sunday of All Saints. This period can be broken down into the following periods:

Synaxarion (Greek: Συναξάριον; Romanian: Sinaxar)—The Synaxarion contains for each day of the year brief lives of the saints and meanings of celebrated feasts, appointed to be read after the Kontakion and Oikos at Matins.

Irmologion (Greek: ῾Ειρμολόγιον; Slavonic: Ирмологий, Irmologii)—Contains the Irmoi chanted at the Canon of Matins and other services.

Priest's Service Book (Greek: ῾Ἱερατικόν, Ieratikon; Slavonic: Слѹжебникъ, Sluzhebnik)Contain the portions of the services which are said by the priest and deacon and is given to a deacon and to a priest with his vestments at ordination.[note 19]

Bishop's Service Book (Greek: Ἀρχιιερατικόν Archieratikon, Slavonic: Чиновникъ, Chinovnik) the portions of the services which are said by the Bishop; for the Canonical Hours, this differs little from what is in the Priest's Service Book.

Gospel Book (Greek: Ευαγγέλιον, Evangelion) Book containing the 4 Gospels laid out as read at the divine services.[note 20]

Patristic writings Many writings from the Church fathers are prescribed to be read at matins and, during great lent, at the hours; in practice, this is only done in some monasteries and frequently therein the abbot prescribes readings other than those in the written rubrics. therefore it is not customary to enumerate all the volumes required for this.

Collections (Greek: Ανθολόγιον, Anthologion; Slavonic: Сборникъ, Sbornik) There are numerous smaller anthologies available[note 21] which were quite common before the invention of printing but still are in common use both because of the enormous volume of a full set of liturgical texts and because the full texts have not yet been translated into several languages currently in use.

Typicon (Greek: Τυπικόν, Typikon; Slavonic: Тѵпико́нъ, Typikon or уста́въ, ustav) Contains all of the rules for the performance of the Divine Services, giving directions for every possible combination of the materials from the books mentioned above into the Daily Cycle of Services.

The fixed portion of the liturgical year begins on September 1. There is also a moveable Paschal cycle which is fixed according to the date of Pascha (Easter), by far the most important day of the entire year. The interplay of these two cycles, plus other lesser cycles influences the manner in which the services are celebrated on a day to day level throughout the entire year.

Traditionally, the Eastern Orthodox and Byzantine Catholic churches used the Julian Calendar to calculate their feast days. Beginning in 1924 the Patriarchate of Constantinople made an adjustment to their liturgical year to bring the fixed cycle in conformity to the modern Gregorian Calendar. The Paschal cycle, however, continued to be calculated according to the Julian Calendar. This composite calendar is known as the Revised Julian Calendar. Constantinople's example was followed by the Church of Greece as well as a number of other autocephalous churches. Today, some churches continue to follow the Julian Calendar while others follow the Revised Julian Calendar. Only the Orthodox Church of Finland has adopted the Western calculation of the date of Pascha (see computus); all other Orthodox Churches, and a number of Eastern Catholic Churches, celebrate Pascha at the same time, according to the ancient rules.

Most of the texts come from the Octoechos, which has a large collections of hymns for each weekday for each of the eight tones; during great lent and, to a lesser degree, the pre-lenten season, the Lenten Triodion supplements this with hymns for each day of the week for each week of that season, as does the Pentecostarion during the pascal season. Also, there are fixed texts for each day of the week are in the Horologion and Priest's Service Book (e.g., dismissals) and the Kathismata (selections from the Psalter) are governed by the weekly cycle in conjunction with the season.

Commemorations on the Fixed Cycle depend upon the day of the calendar year, and also, occasionally, specific days of the week that fall near specific calendar dates, e.g., the Sunday before the Exaltation of the Cross. The texts for this cycle are found in the Menaion.

The commemorations on the Paschal Cycle (Moveable Cycle) depend upon the date of Pascha (Easter). The texts for this cycle are found in the Lenten Triodion, the Pentecostarion, the Octoechos and also, because the daily Epistle and Gospel readings are determined by this cycle, the Gospel Book and Apostle Book. The cycle of the Octoechos continues through the following great lent, so the variable parts of the lenten services are determined by both the preceding year's and the current year's dates of Easter.

The portions of each of the Gospels from the narration of the Resurrection through the end are divided into eleven readings which are read on successive Sundays at matins; there are hymns sung at Matins that correspond with that day's Matins Gospel.

Only autocephalous (self-heading) churches are listed; autonomous churches are considered under their mother churches. Those churches which follow the Julian Calendar exclusively are marked with *, while those that partially use the Julian calendar are marked with (*).

Ukrainian Lutheran Church[10] (which uses liturgical formulae from the Byzantine Rite to form the base text for the Order of Service in the Ukrainian Evangelical Service Book.[11]) As mentioned above, several other Lutheran communities also use this modified version of the Divine Liturgy.

^The Byzantine Catholic churches and, in a substantially modified form, by the ProtestantUkrainian Lutheran Church. It has also been used by the Society for Eastern Rite Anglicanism, German Eastern Rite Community (Ostkirchlicher Konvent), St. Valentine's Lutheran Fellowship of the Grand Canyon Synod (ELCA), and in the Evangelical Lutheran Church of the Augsburg Confession in Slovenia.

^In accordance with Old Testament practice, the day is considered to begin in the evening (Genesis 1:5).

^This is to conform with Psalm 55:17, "Evening, morning, and noonday will I tell of it and will declare it, and He will hear my voice."

^In monasteries, when there is an evening meal, compline is often separated from vespers and read after the meal; in Greek (απόδειπνον/apodeipnon) and Slavonic (Повечерiе/Pov'echeriye), the name for Compline literally means, "After-supper."

^There is also a Psalm 151 which is often included in the Psalter, though it is not actually chanted during the Divine Services.

^excepting in the Russian tradition where they are used weekly on weekdays of Great Lent.

^On non-leap years, the service for 29 Feb. (St. John Cassian) is sung at compline on 28 Feb..

^ abThe liturgical year begins in September, so the volumes are numbered from 1 for September to 12 for August.

^Originally, the deacon's book and the priest's books were distinct, but upon the invention of printing, it was found more practical to combine them.

^ abIn Greek editions the Evangélion is laid out in order of the cycle of readings as they occur in the ecclesiastical year, with a section in the back providing the Gospel readings for Matins, Feasts and special occasions. In the Slavic usage, the Evangélion contains the four gospels in canonical order (Matthew, Mark, Luke, John) with annotations in the margin to indicate the beginning and ending of each reading (and an index in the back).
The Apostól is likewise edited, the Slavonic Apostól having all of the books of the New Testament (excluding the Gospels and Apocalypse) in their entirety, though not in the same order they are found in most English Bibles (Acts is placed first, followed by the Catholic Epistles, etc.).

^For instance, the Festal Menaion contains only those portions of the Menaion that have to do with the Great Feasts; and the General Menaion, et cetera.